Does 2 things: - ensure that the "free_qty" doesn't display a negative value (=> consistent with MO overview + avoids neg "Ready to Produce" values) - ensure that showOptions.availabilities is always a Boolean and never "undefined" (=> avoid traceback when opening overview while in debug mode) closes odoo/odoo#140767 Signed-off-by: Quentin Wolfs (quwo) <quwo@odoo.com>